I. Field of the Invention
This invention relates to a method of starting a high efficiency permanent magnet direct current motor.
II. Discussion of the Prior Art
Prior art methods of starting permanent magnet motors often provide the dangerous capability of demagnetizing the magnet motors where the on-off switch to the motor circuit is normally controlled by a triac motor control switching unit. Rapid movement of the main control switch may energize the triac circuit in rapid on-off succession which could impose maximum initial start-up voltage on the motor and thereby cause demagnetizing current to flow to the motor. These motors, particularly high efficiency models, produce maximum torque at locked rotor conditions and consequently have high inrush amperes capable of demagnetizing their magnets.